En Prison Rule

European and French Roulette have the best odds due to the "En Prison" rule.  The rule applies to when you land on "0".  There is only one ZERO which already increased your odds.  When landing on ZERO your money does not leave the table if you have even money bets.

The wheel spins again and if you win then your get your even bet.  If, the En Prison rule comes into effect because it landed on ZERO then you get your money back.  If you lose your bet then you lose the original wager.

The En Prison rule cuts the House Edge in half.  This is where players want to be.  The lowest House Edge at 1.35% on even money bets.

Note that there are 37 possibilities rather that 38 in American Roulette with "0" and "00".

This is how the math runs:

E = [18/37 x (+1)] + [18/37 x (-1)] + [1/37 x (-0.5)]

E = -0.0135

House Edge = 1.35%